Klatskin tumor

Klatskin tumor is a term that was traditionally given to a hilar (perihilar) cholangiocarcinoma, occurring at the bifurcation of the common hepatic duct. Typically, these tumors are small, poorly differentiated, exhibit aggressive biologic behavior, and tend to obstruct the intrahepatic bile ducts.

Epidemiology

They are thought to account for up to 25% of all cholangiocarcinomas ¹.

Pathology

Classification

Prognostic staging is defined by the TNM system: perihilar cholangiocarcinoma (staging).

The Bismuth-Corlette system is an anatomic classification well known by surgeons used for preoperative assessment.

Radiographic features

For general imaging features of a cholangiocarcinoma, refer to the main article.

Ultrasound

The presence of a hilar mass with obstruction would raise concern on ultrasound. The reported echotexture according to one study ⁵:

• increased echogenicity relative to surrounding liver ~80%
• reduced echogenicity ~20%
• mixed echogenicity ~2%

Ultrasound may also show an intraluminal mass extending into the bile duct and in a small proportion of cases (4%), there may also be evidence of bile duct wall thickening.

CT

CT demonstrates the intrahepatic biliary radical dilatation. The tumor mass itself is ill-defined and usually invisible, but hilar necrotic lymph nodes or hepatic metastatic deposits can be identified. 

MRI/MRCP

MRCP with its 3D capability is superior to CT to delineate the degree and location of the biliary tree stricture. It is the gold standard method for diagnosis of hilar cholangiocarcinoma. Shouldering and abrupt tapering at the stricture site suggests the diagnosis. Identifying the exact location and involvement can help in preoperative classification.

History and etymology

It is named after Gerald Klatskin (1910-86), American pathologist, New York.

Differential diagnosis

Imaging differential considerations include:

• biliary inflammatory pseudotumor: can be indistinguishable on imaging ⁶
• hepatic tuberculosis ⁸
• autoimmune cholangitis ⁹
• benign fibrosing disease at the hepatic confluence ¹⁰
• hepatocellular carcinoma ¹¹
• gallbladder carcinoma (invading the bile duct) ¹²

See also

• cholangiocarcinoma
• cholangiocarcinoma staging